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• In Servlet 2.3,It is part of the Java Servlet as defined but they have their own specific functionalities.


• Listeners are defined as Java interfaces.


• Listeners achieve some tasks during Life Cycle of Application for Developers.


• Listener gives us a great control over application without disturbing architecture of the application.

Servlet Listener Interfaces

Package:-javax.Servlet Interface Name:-ServletContextListener. contextInitialized():- Creates Servlet Context. contextDestroyed():- Destroy Servlet Context.

Package:-javax.Servlet Interface Name:-ServletContextAttributeListener attributeAdded:-Add the Attribute of Servlet Context Object. attributeReplaced:-Replacement the Attribute of Servlet Context Object. attributeRemoved:-Removal the Attribute of Servlet Context Object.

Package:-javax.Servlet.http Interface Name:-HttpSessionListener sessionCreated():-Create and invalidate the Session. sessionDestroyed():-Timeout the session

Package: javax.Servlet.http Interface:-HttpSessionAttributeListener. attributeAdded():-Adds the Session Attribute. attributeReplaced():-Replacement of Session Attribute. attributeRemoved()Remove the Session Attribute.

Servlet Listener Event Classes

Class	Methods
ServletContextListener	getServletContext()
ServletContextAttributeEvent extends ServletContextEvent	getName() getValue()
HttpSessionEvent	getSession()
HttpSessionBindingEvent extends HttpSessionEvent	getName() getValue()